Conventional lighting or surge arresters are typically connected to power lines to carry electrical surge currents to ground, thereby preventing damage to lines and equipment connected to the arresters. Arresters offer high resistance to normal voltage across power lines, but offer very low resistance to surge currents produced by sudden high voltage conditions caused by, for example, lightning strikes, switching surge currents or temporary overvoltages. After the surge, the voltage drops and the arrester normally returns to a high resistance state. However, upon arrester malfunction or failure, the high resistance state is not resumed, and the arrester continues to provide an electrical path from the power line to ground. Ultimately, the line will fail due to a short circuit condition or breakdown of the distribution transformers, and the arrester will require replacement.
To avoid line lockout, disconnector assemblies are commonly used in conjunction with arresters to separate a malfunctioning arrester from the circuit and to provide a visual indication of arrester failure. Conventional disconnector assemblies have an explosive charge to destroy the circuit path and physically separate the electrical terminals. Examples of such disconnector assemblies are disclosed in U.S. Pat. No. 5,952,910 to Krause and U.S. Pat. Nos. 5,057,810 and 5,113,167 to Raudabaugh, as well as U.S. Pat. No. 5,434,550 to Putt, U.S. Pat. No. 4,471,402 to Cunningham and U.S. Pat. No. 4,609,902 to Lenk, the subject matter of each of which are hereby incorporated by reference.
Conventional surge arrester modules include a plurality of Bellville washers to keep compression on the blocks. The Bellville washers compress the blocks and take up the tolerance of the block stack as the block stack relaxes. Removing the Bellville washers requires another method for compressing the blocks.
Accordingly, a need exists for an improved surge arrester with a mechanism for compressing the blocks of the block stack wrapped by a fiberglass material.